Lamborghini Miura Jota
In 1970, Lamborghini development driver Bob Wallace used chassis #5084 to create a test mule that would conform to the FIA's Appendix J racing regulations.
The car was appropriately named the Miura Jota (the pronunciation of the letter 'J' in Spanish). Only one was ever built, which was eventually sold to a private buyer after extensive testing. In April 1971, the car crashed on the yet-unopened ring road around the city of Brescia, and burned to the ground.
Source: Lamborghini press